Mariner of the Seas sails from New Orleans on Saturday, March 13

Likely: Julia Street Cruise Terminal (Norwegian / Royal Caribbean)

Taken from this ship's recent history rather than published for this sailing. Your boarding documents decide.

7 nights

Only as the source publishes it — never counted off the next departure.

Your cruise line's window wins

Most cruise lines assign an arrival window during online check-in — set yours as soon as check-in opens, since the best slots go first. Don't arrive before your window opens: terminals typically hold early arrivals outside, so getting there early buys you nothing. Experienced cruisers most often point to early afternoon, once the first rush has cleared, as the smoothest time to walk in. Follow the check-in instructions your cruise line sends you — they always take priority over general guidance.